Scientists investigate death of 10,000 endangered 'scrotum' frogs in Peru

Previous studies had shown high levels of heavy metals in the lake caused by mining tailings from both formal operations and illegal gold mining in surrounding rivers, he said. They include lead, cadmium, mercury, arsenic, iron and zinc.

“Villagers had been cleaning garbage from the river which may have disturbed the sediments,” Elias added, although he stressed post-mortem studies on the frogs had not yet been completed.

https://www.theguardian.com/environment/2016/oct/19/scientists-investigate-death-of-10000-endangered-scrotum-frogs-in-peru